Engine flywheel torque control

Abstract

A control system/method for controlling engine (12) flywheel (T FW ) torque in a vehicular powertrain system (10) including an electronically controlled engine and a torque load limited drivetrain system (11) is provided. The control will sense values of a control parameter (GR, OS) indicative of potential overloading of the drivetrain at maximum engine flywheel torque and will cause engine flywheel torque to be limited to a value less than the maximum value thereof. Flywheel torque is determined as a function of torque values available on the vehicle electronic data link (DL).

I claim: 
     
       1. A method for controlling a vehicular powertrain system (10) comprising a fuel-controlled engine (12) drivingly connected to a vehicular drivetrain system (11) including a multiple-ratio, change-gear transmission (14) and a drive axle (19), said engine having a maximum output torque and an engine controller responsive to command signals to control fueling of the engine and, in at least one mode of operation, effective to limit gross engine torque, said drivetrain having a predetermined maximum torque loading capacity, said drivetrain configured such that an expected torque loading on said drivetrain under a predetermined set of drivetrain operating conditions defined by an engine output torque equal to or less than said maximum engine torque and transmission engaged ratio will exceed said predetermined maximum torque loading capacity, said method comprising: determining as a function of gross engine torque a value of a control parameter indicative of engine flywheel torque;   sensing the value of a control parameter indicative of transmission engaged ratio; and   causing said engine controller to limit gross engine torque to a value corresponding to an engine flywheel torque value determined as a function of transmission engaged gear ratio.   
     
     
       2. The method of claim 1 wherein said engine controller is microprocessor-based and communicates over an electronic data link. 
     
     
       3. The method of claim 1 wherein said transmission is manually shifted. 
     
     
       4. The method of claim 2 wherein said transmission is manually shifted. 
     
     
       5. A system for controlling a vehicular powertrain system (10) comprising a fuel-controlled engine (12) drivingly connected to a vehicular drivetrain system (11) including a multiple-ratio, change-gear transmission (14) and a drive axle (19), said engine having a maximum flywheel torque and an engine controller responsive to command signals to control fueling of the engine and, in at least one mode of operation, effective to limit gross engine torque, said drivetrain having a predetermined maximum torque loading capacity, said drivetrain configured such that an expected torque loading on said drivetrain under a predetermined set of drivetrain operating conditions defined by transmission engaged gear ratio and an engine torque less than or equal to said maximum engine output torque will exceed said predetermined maximum torque loading capacity, said system comprising: means to determine as a variable function of gross engine torque the value of a control parameter indicative of current engine flywheel torque (T FW );   means for sensing the value of a control parameter indicative of transmission engaged ratio; and   means for causing said engine controller to limit engine flywheel torque by limiting gross engine torque to an engine flywheel torque value determined as a function of transmission engaged ratio.   
     
     
       6. The system of claim 5 wherein said engine controller is microprocessor-based and communicates over an electronic data link. 
     
     
       7. The system of claim 5 wherein said transmission is manually shifted.